Changes necessary to following ES5 semantics and matching Safari - in ES3
the same RegExp object was generated by each evaluation of the RegExp literal.
Fixes bug 704.

Review URL: http://codereview.chromium.org/3034060

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@5198 ce2b1a6d-e550-0410-aec6-3dcde31c8c00